This work introduces the new trimetallic complex CoPd2(HBPDC)2Cl4·(H2O)4(H2BPDC = 2,2'-bipyridine-4,4'-dicarboxylic acid) as a highly efficient and more cost-effective catalyst for a Suzuki-Miyaura reaction proceeding in water, without additives and under aerobic conditions. Catalytic studies revealed a synergistic Co-Pd cooperativity, fostered by ligation through H2BPDC, and accounting for the superior performance of the heterobimetallic complex vs. its Co-free counterpart.